Fitting correlated hadron mass spectrum data

Abstract

We discuss fitting hadronic Green functions versus time t to extract mass values in quenched lattice QCD. These data are themselves strongly correlated in t. With only a limited number of data samples, the method of minimizing correlated ${\mathrm{\ensuremath{\chi}}}^{2}$ is unreliable. We explore several methods of modeling the correlations among the data set by a few parameters which then give a stable and sensible fit even if the data sample is small. In particular these models give a reliable estimate of the goodness of fit.